The Science, Evidence, and Practice of Dietary Interventions in Irritable Bowel Syndrome. Brian Lacey Clinical Gastroenterology and Hepatology 2015;13:1899-1906

Pelvic PT Distance Journal Club

September 7, 2016

Jane O’Brien Franczak, PT, MSPT

Summary: This article is a review of pathophysiologic mechanisms that may explain IBS food related symptoms (sx) and evaluates clinical trials of specialized diets used to treat IBS sx.

Premise: Food can cause GI distress due to stimulation of mechanoreceptors and chemoreceptors (ie capsaicin) or alterations in GI transit, intestinal osmolarity and secretion. IBS patients report more food related issues than healthy controls

What causes food symptoms? :

Food Allergies

1. IgE mediated = Rapid onset, ie nuts, wheat, shellfish, strawberries.

Sx of nausea, dysphagia, abdominal pain, vomiting, diarrhea (urticaria)

2. Non IgE -mediated : cell mediated response (T helper 2 cells), delayed onset, IgG antibodies are more prevalent with IBS pts. Sx= GI only.

Food Intolerances

Non- immunologic events, (non-celiac gluten sensitivity, presence of chemicals in foods, histamine, enzyme defects, short chain carbohydrates.)

70% of IBS patients report symptoms representative of food intolerances.

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Etiology of Food Intolerances

*Chemical additives  Leads to (=>) increased gastric acid production, accelerated colonic transit (caffeine) smooth ms. contraction ( histamine) or stimulation of smooth ms.contractions. (salicylates).

*Non Celiac Gluten sensitivity (NCGS) ie wheat ( 2 studies: 1 found 6% prevalence other found 1 in 4pts self reported NCGS fulfill the dx.  Sx of NCGS are identical to Celiac but transglutaminase antibodies are not presented small intestines morphologically normal

*Enzyme defects i.e.  lactase deficiency 30% caucasians 70% Asians (

*Transport defects - Fructose malabsorption causes IBS distress/gas

Sugar Alcohol Manitol, sorbitol, xylitol, maltitol, erythritol

Excess Fermentation of Short chain carbos. (FODMAPS) produce intestinal gas and GI sx in IBS and healthy controls.

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Intestinal Permeability

Newer concept. More present in IBS-D vs. IBS-C

2/3 of IBS patients (n=36) challenged with wheat soy, milk and yeast and has significant increase in number of epithelial breaks, intraepithelial lymphocytes and size of intervillous spaces.

 

Visceral hypersensitivity

2 studies showed IBS patients ingested lactose. More sensitive to gas production than healthy patients with ulcerative colitis, Capsacin => more distress.

 

Small Intestine Bacterial Overgrowth ( SIBO)

May cause GI sx in some IBS pts. No gold standard/accurate test is a problem.

 

Gut Microbiome

(The gut flora )Diversity exists btw different disease states   (Inflammatory bowel vs. IBS) within disease states IBS subtypes.

Specific dietary Interventions for IBS

Review of studies

Fiber supplementation

Mainstay therapy for IBS for years. Unknown mechanism of action. Fiber’s benefit may reflect colonic fermentation with production of short chain fatty acids or it acts as prebiotic.  More effective than placebo at improving IBS sx.

Elimination diets

Symptom improvement followed by worsening when suspect foods were reintroduced. No good for long term help

IgG based elimination diets

3 month trial.

26% improvement if fully adherent; worsened upon reintroduction.

Very Low Carb diets

51% calories from fat

45% proteins

4% carbos

Impact was relief of IBS sx for 2 of 4 wk study.

Low Fructose/FructanDiet

Relates to fructose malabsorption. 77% of patients were compliant =>74% positive response (abdominal pain, gas, nausea, diarrhea, constipation )

Low /No Gluten diet

Patients who had prior improvements without gluten. Reintroduced it => sx of bloating, pain and sx

Low FODMAP

Fermentable oligosaccarides, disaccaride, monosaccaride, polyol diet => reduction of sx.

Patients with fructose intolerance ID’d with breath test more likely to respond to diet than (-) test.

Concluding remarks

Studies hard to compare bec of lack of standardized diet.

Lack of safe, easy, inexpensive and reliable test to diagnose food intolerance.

Considerations:

1. Foods may Exacerbate sx: Lactose, fructose, excess fiber, fructans and galactans.

2. dx of celiac disease

3. Avoid expensive commercial tests

4. sx may be caused by Chemicals in NCGS so gluten free diet may be appropriate. for IBS-d, mixed IBS, its and ex of gas and bloating.

5. Low FODMAP diet should be considered for those who failed other interventions. 4 week trial.

6. studies have been on women.

7. little info on HOW the IBS diets affect gut micro biome and effects elsewhere in body.

 

Terms

Probiotics = live bacteria in yogurt, dairy

Prebiotics - special forms of plant fiber that nourishes goo bacteria in colon. Act as fertilizer for good bacteria that are there to promote growth of goo bacteria lessen anxiety stress and depression

Archaea- similar to bacteria

Prokaryotes : both are micro organisms.

Questions:

1.  Are you familiar with Low FODMAP or IgG diets being used by patients?

Do you work with MDs /naturopaths who order these types of diets?

2. What are your thoughts about limiting the adverse intake so the elimination can improve?